Stationary induction apparatus



May 26,1925.

A. B. HENDRICKS, JR

.STATIONARY INDUCTION APPARATUS Filed Feb. 24, 1920 5 Sheets-Sheet 1Inventor JHlan B.Hendr-icks Jn,

Hi8 flttorne May 26, 1925.

A. B. HENDRICKS, JR'

STATIONARY INDUCTION APPARATUS 3 Sheets-Sheet 2 Filed Feb. 24', 1920 CT:dsr-icks Jr; mm

Invent n I 4 v HIS fitter-neg.

nEHe 5 Ila ' May 26, 1925. 1,539,670

, A. B. HENDRICKS, JR

STATIONARY INDUCTION APPARATUS Filed Feb. 24, 1920 3 Sheets-Sheet fi s.

Inventor-2 94 I Ian B. Hendricks J17,

His Attorney tion.

Patented May 26, l25.

UNITED STATES PATENT OFFICE.

ALLAN B. HENDRICKS, JR, OF PITTSFIELD, MASSACHUSETTS, ASSIGNOR TOGENERAL ELECTRIC COMPANY, A CDRPORATION OF NEW YORK.

STATIONARY INDUCTION APPARATUS.

Application filed February 24, 1920. Serial No. 360,911.

To a1 Z whom it may cmwem:

. Be it known that I, ALLAN B. HE.- nuIoKs, J r., a citizen of theUnited States, residing at Pittsfield, in the county of Berkshire, Stateof Massachusetts, have invented certain new and useful Improvements inStationary Induction Apparatus, of which the following is'aspecification.

My invention relates to transformers and the like, and has for itsobject an improved arrangement of parts whereby a strong and veryeconomical construction results.

In large power transformers, the mag netic repulsion between the primaryand secondai windings produces very great stresses in the core and framesupporting such windings. For large units of the type to which Icontemplate applying my invention, should a short circuit suddenly occurin the system supplied by such units, these repulsive forces may thenincrease with such rapidity that, unless the windings are very carefullybalanced, something is likely to give way.

In the practice of my invention I avoid such eventualities by providingvery rugged supports for the windings in addition to providing for asnearly a complete magnetic balance between the primary and secondary, asis possible. In effecting this balance I provide a correspondingdistribution of the turns of the primary and secondary along the windingaxis and also locate both windings with their magnetic centerscoinciding in position as nearly as possible along the winding axis.

For a more complete understanding of the nature and objects of myinvention reference should be had to the following detailed descriptiontaken in connection with the accompanying drawing in which:

Fig. 1 is a view, partly in section and partly in side elevation, of atransformer constructed in accordance with -my inven- Fig. 2 is a topplan view, parts of the core being broken away, showing the means forsecuring the windings in their proper relative positions on the core.Fig. 3 is a fragmentary sectional view showing further details. Figs. 4and 5 are perspective views of the assembled low voltage winding and thecore respectively. 6 is a detail view of an adjustable device forsecuring the windings in' position.

Referring now to the drawings, 10 denotes a magnetic core having acentral leg 11 and two side legs 12. The low voltage winding 14 and thehigh voltage winding 15 are concentrically arranged about the centralleg 11 and are supported at their bases by abutments 16 secured tothebottom core clamps 17.

Between the windings 14 and 15 and the abutments 16 are placed spacingelements 18 and 19 for supporting the low voltage and high voltagewindings 'in proper positions with respect to each other and also withrespect to the core. Insulating blocks 20 are also shown asresting onthe abutmerits 16 to serve as a suitable base on which to arrange thespacing elements 18 and 19.

Each of the windings 14 and 15, on account of the high duty required ofit, is preferably composed of disc-coils which are spaced apart byspacing elements disposed between the coils at preferably equi-distantlyspaced points; those in the low voltage winding being indicated at 22and the ones in the high voltage winding at 23. The down turned portionsof these L-spacers serve to keep the coils properly spaced from theinterposed insulating cylinders 2 1 and 25, which serve as barriersbetween the core and windings and between the windings themselves. Amongthe high voltage coils additional annular barriers or collars 26 aredisposedat suitable points. Among the low voltage coils, the L-spacers,at predetermined points, are prolonged as shown at 27 to properly spaceapart the insulating cylinders 24.- and 25.

The lower terminal of the high voltage winding is connected to the coreand grounded as indicated in Fig. 1. This end of the winding istherefore maintained at ground potential but in operation the voltageincreases along the winding to its maximum value at the upper or highvoltage end of the winding. Much more insulation is thus required andthe space available for the winding is thus much less at its upper orhigh voltage end than at its lower or grounded end, the availablewinding space increasing in size as the voltage decreases from the 'highvoltage end to the grounded end of the winding. Thus, the high voltagewinding may have a larger number of turns per unit distance along thecore at its grounded or low voltage end than at its high voltage end,the number of turns assembled turns along the core.

per unit distance along the core decreasing with the available windingspace and inversely with the voltage toward the high volta e end. Thisresults in a non-uniform distribution of the high voltage. windingAnother feature of construction which contributes to the nonuniformityof distribution of the high voltage winding along the core is thepresence of the large buffer coils 15 and 15 at the upper and lower endsof the winding. 7 The conductor in these end coils is of larger crosssection than that of the rest of the winding and it is also providedwith heavier insulation to withstand the effects of high voltagetransient currents. entering the winding. Because of the larger crosssection of conductor and the heavier insulation in these end coils, thenumber of turns per unit distance along the core is reduced. The highand, low voltage windings are with their magnetic centers coinciding toeliminate as far as possible the displacement forces between the twowindings. It is desirable, however, that such forces be eliminated notonly between each winding and the other as a whole but also between eachsection of each winding and the corresponding section of the other so asto reduce as much as possible the stresses between the different windingsections. In accordance with the invention, therefore, the turns of thelow voltage winding are distributed nonuniformly along'the core so thatthis distribution may'correspond, so far as practicable, with thenecessarily nonuniform distribution-of the highvoltage winding. I

In order that each winding may be located as accurately as possible withrespect to the core and the other winding, I provide. each with anadjustable securing means at the top of the winding, such means for thelow voltage winding being shown at 30, while that for the highvoltagewinding is shown at 3].. Immediately beneath these adjustingmeans, and between them and their respective windings are placedsuitable insulating barriers and spacing devices, as shown at 32 and 33respectively.

The securing devices 30 and 31 may have any convenient form, such asthat shown in detail in Fi 6; here 30 denotesa nut in which a suit-a lescrew threaded stud 30* engages, and whose height with respect to thenut 30 may be adjusted by means of a suitable tool adapted to engage thenut, as

' for instance with the rib 30 on the nut.

A desirable location and distribution of these securing means 30 and 31to hold down the windings 14: and 15'is shown in Fig. 2. These securingmeans are arranged to react against an abutment 36 secured against theupper core clamp 37 in substantially a similar manner to the abutment 16at the bottom of the core.

The abutments, 16 and 36 on the core, as clearly shown in Fig. 5, make avery rugged structure capable of withstanding very severe stresses whichmay occur in service from any slight unbalancing ofthe magnetic forcesbetween the windings 14 and 15 or which may arise from shrinkage in oneor both of the windings. This arrangement of abutments for the windingsgreatly sim lifies the core bracing, as will be rea ily appreciated fromthe drawings and at the same time admits of a simple and rugged coreliftingnieans being secured to the core as shown at 40 without resort toanv special form of core rigging.

aving now described my invention and the best means at present known tome for carrying the same into effect, I would have it understood thatthis is merely illustrative, and that I do not mean to be limitedthereby to the precise details shown, nor restricted in the choice ofrecognized equivalents except as defined in my claims hereunto annexed.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. In a high voltage transformer, the combination with a core, of a highvoltage winding with its turns distributed non-uniformly along said coreto withstand the effects of the high voltage, and a low voltage windingwith its electrical center coinciding in position along the core withthat of the high voltage winding, the distributionnof the turns of thelow voltage windin along the core substantially correspon ing to that ofsaid high voltage turns to reduce displacement forces between saidwindings.

2. In a high voltage transformer, the combination with a core,of a highvoltage winding with one end grounded, the number of turns of said highvoltage winding per unit distance along the core decreasing from itsgrounded end, and a low voltage winding with its electrical centercoinciding in position along the core with that of the high voltagewinding, the distribution of the turns of the low voltage winding alongthe cone substantially corresponding to that of said high voltage turnsto reduce displacement forces between said windings.

In witness whereof, I h.ve hereunto set my hand this 19th day of Feb,1920.

ALLAN B. HENDRICKS, JR.

